OCR Text |
Show NOx, ppm (@3% Oxygen) 1 , 200 1 , 000 Conventional Burners BOO 600 400 200 o o 200 400 600 BOO 1,000 1,200 1,400 1,600 Combustion Air Preheat d e g F Figure 1 gases. GRI has supported two low NOx burner development programs, one aimed at forging and similar metals heating applications, and the second aimed at steel reheating. The burners that have resulted use one or the other of these techniques. The Arthur D. LittlelMITlHauck "StAR" Burner The burner intended for forging applications will be the first to enter commercial use. The StAR, or Staged Air Recirculating, burner combines air staging with external flue gas recirculation to achieve NOx emissions below 50 ppm (at 3% 02) for systems using air preheat as high as 1500 F. Two 2MM Btulhr burners are currently installed in a forging shop in Southern California, where they have been performing satisfactorily for several months. NOx emissions levels have been <25 ppm at full load and <60 ppm at 2: 1 turndown, both with 800 F preheat. CO has been <30 ppm in all cases. Temperature uniformity, which is a critical performance parameter for the operation, has been as good or better than similar furnaces fitted with conventional burners. -Plans call for a field test of a commercial design of the StAR burner this summer, with market introduction planned following completion of the test. Additionally,other designs for the burner, including a design optimized for ambient air operation and a 10-fold scaleup to 20 MM Btulhr. are planned. 3 |